pgsql: Re-enable max_standby_delay = -1 using deadlock detection on

Log Message:
-----------
Re-enable max_standby_delay = -1 using deadlock detection on startup
process. If startup waits on a buffer pin we send a request to all
backends to cancel themselves if they are holding the buffer pin
required and they are also waiting on a lock. If not, startup waits
until max_standby_delay before cancelling any backend waiting for
the requested buffer pin.

Modified Files:
--------------
pgsql/src/backend/storage/ipc:
procsignal.c (r1.4 -> r1.5)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/storage/ipc/procsignal.c?r1=1.4&r2=1.5)
standby.c (r1.11 -> r1.12)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/storage/ipc/standby.c?r1=1.11&r2=1.12)
pgsql/src/backend/storage/lmgr:
proc.c (r1.215 -> r1.216)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/storage/lmgr/proc.c?r1=1.215&r2=1.216)
pgsql/src/backend/tcop:
postgres.c (r1.587 -> r1.588)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/tcop/postgres.c?r1=1.587&r2=1.588)
pgsql/src/backend/utils/misc:
guc.c (r1.538 -> r1.539)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/misc/guc.c?r1=1.538&r2=1.539)
pgsql/src/include/storage:
proc.h (r1.119 -> r1.120)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/storage/proc.h?r1=1.119&r2=1.120)
procsignal.h (r1.4 -> r1.5)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/storage/procsignal.h?r1=1.4&r2=1.5)
standby.h (r1.7 -> r1.8)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/storage/standby.h?r1=1.7&r2=1.8)